When I was 15 or so, I started dating an incredibly beautiful and intelligent Hawaiian/Japanese Mormon. She seemed pretty in to me, but she was also very devoted to her religion. I had a pretty indifferent attitude towards any religion at the time, and I deemed her to be "too much to handle and deal with". I didn't tell her that specifically, but I did tell her that I didn't want to pursue anything with her. To this day I greatly regret not even attempting any long term relationship with her. I think we lasted 2 weeks before my jerkolantern turned on. Regardless of how incredibly beautiful she was, I regret not taking the time to learn anything about her religion from a first hand experience, or even trying to get to know her more. Sure I can look it all up now, but that's different. These are the things you think of well after the fact, past the point of no return. But I feel no matter what OP, you should be open to anything, and be very vocal with your partner. It's the best and only way.
Edit - except when the significant other seems to be taking direction from outside forces, seemingly going against her own decisions. That's a whole new can of worms that requires a conversation with the SO, but I honestly don't know what the best course of action would be after that.
